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Update esp32_i2s_parallel_v2.c

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mrfaptastic 2021-02-19 09:39:17 +00:00
parent 1c88590d6e
commit 4944926fdf
1 changed files with 9 additions and 7 deletions
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esp32_i2s_parallel_v2.c
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@ -207,7 +207,7 @@ esp_err_t i2s_parallel_driver_install(i2s_port_t port, i2s_parallel_config_t* co
dev->sample_rate_conf.rx_bits_mod = bus_width; dev->sample_rate_conf.rx_bits_mod = bus_width;
dev->sample_rate_conf.tx_bits_mod = bus_width; dev->sample_rate_conf.tx_bits_mod = bus_width;
dev->sample_rate_conf.rx_bck_div_num = 1; dev->sample_rate_conf.rx_bck_div_num = 1;
dev->sample_rate_conf.tx_bck_div_num = 1; // datasheet says this must be 2 or greater (but 1 seems to work) dev->sample_rate_conf.tx_bck_div_num = 2; // datasheet says this must be 2 or greater (but 1 seems to work)
// note: because it's 1 here, not 2, we need to clkm_div_num = clkm_div_num * 2 // note: because it's 1 here, not 2, we need to clkm_div_num = clkm_div_num * 2
// No support for fractional dividers (could probably be ported from official serial i2s driver though) // No support for fractional dividers (could probably be ported from official serial i2s driver though)
@ -216,22 +216,24 @@ esp_err_t i2s_parallel_driver_install(i2s_port_t port, i2s_parallel_config_t* co
// https://easyvolts.com/2018/08/14/esp32-40msps-oscilloscope-project-is-closed-and-here-is-why/ // https://easyvolts.com/2018/08/14/esp32-40msps-oscilloscope-project-is-closed-and-here-is-why/
// and https://github.com/espressif/esp-idf/issues/2251 // and https://github.com/espressif/esp-idf/issues/2251
// Igor - "Frequencies above 20MHz do not work in I2S mode." // Igor - "Frequencies above 20MHz do not work in I2S mode."
//
// 16bit parallel I2S = calculated clk_div_main (per line ~142) of 4 // 16bit parallel I2S @ 10Mhz = calculated clk_div_main (per line ~142) of 4
// 16bit parallel I2S @ 20Mhz = calculated clk_div_main (per line ~142) of 2
dev->clkm_conf.val=0; // Clear the clkm_conf struct dev->clkm_conf.val=0; // Clear the clkm_conf struct
dev->clkm_conf.clka_en=0; // Use the 160mhz system clock (PLL_D2_CLK) when '0' dev->clkm_conf.clka_en=0; // Use the 160mhz system clock (PLL_D2_CLK) when '0'
dev->clkm_conf.clkm_div_b=0; // Page 310 of Technical Reference Manual - Clock numerator dev->clkm_conf.clkm_div_b=0; // Page 310 of Technical Reference Manual - Clock numerator
dev->clkm_conf.clkm_div_a=0; // Page 310 of Technical Reference Manual - Clock denominator dev->clkm_conf.clkm_div_a=1; // Page 310 of Technical Reference Manual - Clock denominator
// //
// Final Mhz output = // Final Mhz output =
// Output = 80000000L / tx_bck_div_num / (clkm_div_num + (clkm_div_b/clkm_div_a) ) // Output = 80000000L / tx_bck_div_num / (clkm_div_num + (clkm_div_b/clkm_div_a) )
// Note: clkm_div_num must only be set AFTER clkm_div_b, clkm_div_a, etc. Or weird things happen! // Note: clkm_div_num must only be set here AFTER clkm_div_b, clkm_div_a, etc. Or weird things happen!
// dev->clkm_conf.clkm_div_num = (clk_div_main*2)+1; dev->clkm_conf.clkm_div_num = clk_div_main;
dev->clkm_conf.clkm_div_num=80000000L/(conf->sample_rate + 1);
//dev->clkm_conf.clkm_div_num=80000000L/(conf->sample_rate + 1);
//printf("esp32_i2s_parallel_2.c > I2S clock divider is %d \n", clk_div_main*2); //printf("esp32_i2s_parallel_2.c > I2S clock divider is %d \n", clk_div_main*2);